One or more embodiments of the subject matter described herein generally relate to a device or method for accessing an interior space that extends along an anatomic layer about an organ, such as the pericardium.
The human or animal body includes different anatomic layers that separate different regions of the body. In many cases, it is desirable to insert a device through an anatomic layer without subjecting the anatomic layer or any structures behind the layer to trauma. For example, the heart is enveloped within a multi-layered sac called the pericardium. Two of the layers, the visceral pericardium and the parietal pericardium, are normally in close contact with a thin layer of pericardial fluid therebetween. This space may be referred to as the pericardial space. Access to the pericardial space may be necessary or beneficial under a variety of circumstances. For instance, with access to the pericardial space, leads for a pacemaker or defibrillator may be implanted or placed at a particular location, pericardial fluid may be drained, drugs may be delivered more directly to a portion of the heart, and a variety of other diagnostic, therapeutic and/or surgical procedures may be performed.
One method of accessing the pericardial space includes inserting a shaft through a skin incision below the xiphoid. The shaft has a distal end that may be advanced into the body until the distal end presses against the pericardium. In the known method, the distal end of the shaft includes a number of pointed tines that are configured to grab and pull the parietal pericardium. More specifically, the tines are shaped so that when the shaft is rotated, the tines pierce the parietal pericardium and become embedded therein. In this manner, the distal end of the shaft effectively grabs the parietal pericardium. The multi-tined shaft may then be pulled backward to separate the parietal and visceral pericardia and expand the size of the pericardial space. With the pericardial space expanded, a Tuohy needle may be inserted through the shaft and pierce the parietal pericardium, thereby accessing the pericardial space. Certain tools and objects (e.g., a guidewire) may then be inserted into the pericardial space through the Tuohy needle.
In another known procedure, a distal end of a percutaneous tube is positioned against the parietal pericardium in a similar manner as described above. The tube has a flow channel that extends to an opening of the distal end. However, instead of grabbing the parietal pericardium with tines, the channel may be evacuated to effectively grab a portion of the parietal pericardium. Specifically, the vacuum pulls a localized portion of the parietal pericardium into the opening to form what is called a pericardial bleb. With the bleb formed in the opening, a needle may pierce the bleb to access the pericardial space.
Although known access tools, such as the multi-tined shaft and evacuated percutaneous tube, may be suitable for gaining access to the pericardial space, the tools have certain limitations, especially after access is obtained. For example, as described above, a number of different objects may be moved through the access tools after gaining access to the pericardial space. The insertion and removal of these objects may require careful manipulation of the access tool and the objects. Frequently, the doctor may use both hands to hold the access tool, which limits the doctor's ability to insert or remove the object through the access tool. In addition, with respect to the multi-tined shaft, inadvertent rotation of the shaft may withdraw the tines from the parietal pericardium causing the shaft to release the parietal pericardium before the procedure is completed. This undesired release further complicates the procedure and may increase the risk of trauma to the patient.
Accordingly, there is a need for a medical device that enables a doctor or other qualified person to access a space located behind an anatomic layer of an individual and allow the person to insert and remove objects without the limitations of known access tools. There is also a general need for more operator-friendly medical devices that reduce the risk of trauma to the patient during a medical procedure.